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Date:   Wed, 13 Sep 2023 15:59:41 +0100
From:   Conor Dooley <conor@kernel.org>
To:     Herve Codina <herve.codina@bootlin.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, Andrew Lunn <andrew@lunn.ch>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>, Lee Jones <lee@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Qiang Zhao <qiang.zhao@nxp.com>, Li Yang <leoyang.li@nxp.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        Shengjiu Wang <shengjiu.wang@gmail.com>,
        Xiubo Li <Xiubo.Lee@gmail.com>,
        Fabio Estevam <festevam@gmail.com>,
        Nicolin Chen <nicoleotsuka@gmail.com>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Randy Dunlap <rdunlap@infradead.org>, netdev@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, alsa-devel@alsa-project.org,
        Simon Horman <horms@kernel.org>,
        Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH v5 08/31] dt-bindings: soc: fsl: cpm_qe: cpm1-scc-qmc:
 Add support for QMC HDLC
Message-ID: <20230913-unburned-overturn-41b83e1eed25@spud>
References: <20230912081527.208499-1-herve.codina@bootlin.com>
 <20230912101018.225246-1-herve.codina@bootlin.com>
 <20230912-capable-stash-c7a3e33078ac@spud>
 <20230913092640.76934b31@bootlin.com>
 <20230913-unruly-recite-7dbbbd7e63e0@spud>
 <20230913165250.02bab2ad@bootlin.com>
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On Wed, Sep 13, 2023 at 03:56:16PM +0100, Conor Dooley wrote:
> On Wed, Sep 13, 2023 at 04:52:50PM +0200, Herve Codina wrote:
> > On Wed, 13 Sep 2023 15:42:45 +0100
> > Conor Dooley <conor@kernel.org> wrote:
> >=20
> > > On Wed, Sep 13, 2023 at 09:26:40AM +0200, Herve Codina wrote:
> > > > Hi Conor,
> > > >=20
> > > > On Tue, 12 Sep 2023 18:21:58 +0100
> > > > Conor Dooley <conor@kernel.org> wrote:
> > > >  =20
> > > > > On Tue, Sep 12, 2023 at 12:10:18PM +0200, Herve Codina wrote: =20
> > > > > > The QMC (QUICC mutichannel controller) is a controller present =
in some
> > > > > > PowerQUICC SoC such as MPC885.
> > > > > > The QMC HDLC uses the QMC controller to transfer HDLC data.
> > > > > >=20
> > > > > > Additionally, a framer can be connected to the QMC HDLC.
> > > > > > If present, this framer is the interface between the TDM bus us=
ed by the
> > > > > > QMC HDLC and the E1/T1 line.
> > > > > > The QMC HDLC can use this framer to get information about the E=
1/T1 line
> > > > > > and configure the E1/T1 line.
> > > > > >=20
> > > > > > Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> > > > > > ---
> > > > > >  .../bindings/soc/fsl/cpm_qe/fsl,cpm1-scc-qmc.yaml   | 13 +++++=
++++++++
> > > > > >  1 file changed, 13 insertions(+)
> > > > > >=20
> > > > > > diff --git a/Documentation/devicetree/bindings/soc/fsl/cpm_qe/f=
sl,cpm1-scc-qmc.yaml b/Documentation/devicetree/bindings/soc/fsl/cpm_qe/fsl=
,cpm1-scc-qmc.yaml
> > > > > > index 82d9beb48e00..b5073531f3f1 100644
> > > > > > --- a/Documentation/devicetree/bindings/soc/fsl/cpm_qe/fsl,cpm1=
-scc-qmc.yaml
> > > > > > +++ b/Documentation/devicetree/bindings/soc/fsl/cpm_qe/fsl,cpm1=
-scc-qmc.yaml
> > > > > > @@ -101,6 +101,16 @@ patternProperties:
> > > > > >            Channel assigned Rx time-slots within the Rx time-sl=
ots routed by the
> > > > > >            TSA to this cell.
> > > > > > =20
> > > > > > +      compatible:
> > > > > > +        const: fsl,qmc-hdlc
> > > > > > +
> > > > > > +      fsl,framer:
> > > > > > +        $ref: /schemas/types.yaml#/definitions/phandle
> > > > > > +        description:
> > > > > > +          phandle to the framer node. The framer is in charge =
of an E1/T1 line
> > > > > > +          interface connected to the TDM bus. It can be used t=
o get the E1/T1 line
> > > > > > +          status such as link up/down.   =20
> > > > >=20
> > > > > Sounds like this fsl,framer property should depend on the compati=
ble
> > > > > being present, no? =20
> > > >=20
> > > > Well from the implementation point of view, only the QMC HDLC drive=
r uses this
> > > > property.
> > > >=20
> > > > From the hardware description point of view, this property means th=
at the time slots
> > > > handled by this channel are connected to the framer. So I think it =
makes sense for
> > > > any channel no matter the compatible (even if compatible is not pre=
sent).
> > > >=20
> > > > Should I change and constraint the fsl,framer property to the compa=
tible presence ?
> > > > If so, is the following correct for this contraint ?
> > > >    --- 8< ---
> > > >    dependencies:
> > > >      - fsl,framer: [ compatible ];
> > > >    --- 8< --- =20
> > >=20
> > > The regular sort of
> > > if:
> > > 	compatible:
> > > 		contains:
> > > 			const: foo
> > > then:
> > > 	required:
> > > 		- fsl,framer
> > > would fit the bill, no?
> >=20
> > Not sure.
> > "fsl,framer" is an optional property (depending on the hardware we can =
have
> > a framer or not).
>=20
> Ah apologies, I had it backwards! Your suggestion seems fair in that
> case.

Or actually,
if:
	compatible:
		not:
	 		contains:
	 			const: foo
 then:
 	properties:
 		fsl,framer: false
? That should do the trick in a more conventional way.

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